Coolant Level in filler neck?

[CB900F2]

Hey guys..

Do you mind checking what is the level of your coolant when the motor has fully cooled down...

I noticed my level was near the bottom of the neck, so I topped it off, and I checked it again a few days later after driving and it is a the same level again..

I did notice my over flow bottle level did rise a bit, but my question is, when the motor warms up, and the fluid expands, it should flow to the overflow bottle which is fine, but I thought once the motor starts to cool down, it should draw the coolant back in? Or is it just a one was system?

[Yaris Hilton]

You're right, it's supposed to draw it back in from the overflow tank and keep it full to the radiator cap. Either you have a big enough air bubble in the system so it's not overflowing and sucking back from the tank properly, or your radiator cap or coolant overflow hose is leaking air.

[YarisSedan]

The coolant overflow tank is just that. As liquids heat up they expand and need somewhere to go. That is why there is a hot and a cool line on the overflow tank. You are supose to check it when the vehicle is fully cool or fully hot otherwise you are going to get a false reading. Now it may be overful. But being slightly overfull isnt really a big deal. So no worries. Best time to check it is in the morning before you start the car and on a level surface not on the driveway.

[CB900F2]

Hey guys.. I took a photo of the level, and I have topped of the level twice which in turn has caused my overflow bottle level to rise a bit since when the motor gets hot, the coolant expands into the overflow bottle..

But it doesnt seem to be pulling the coolant back in the system to keep it at the top of the filler neck.. :iono:

Anyone willing to check your coolant level at cold and post a photo?

[Yaris Hilton]

Like I said before, that's not right. You have a leak somewhere.

[CB900F2]

I hear ya... I assume you took a look at your coolant level at cold and the level is at the top??...

There is a thread also going on BITOG also with a number of Yaris owners and they have the exact same coolant level when cold as mine, so it does not seem to be a situation with just my car.. Unless we all have an air bubble, leak or defective rad cap :iono:

Guys. Please chime in and take a look at your coolant level when the motor is cold so we can get a consensus on either it is normal or I and many might have a potential issue


Like I said before, that's not right. You have a leak somewhere.

[kurokoma-kun]

mine does exactly the same.

I just topped off my radiator and reservoir last weekend... yet just as before, tank level rises maybe an inch when hot, coolant level is below junction of filler neck when cold.

[Yaris Hilton]

I'm describing how a coolant recovery system is supposed to work. If Toyota doesn't fill the radiators to the top, it may not function properly. The original intent of the device was to purge all air out of the cooling system by filling the radiator to the cap, letting expansion of the hot coolant be taken care of by overflow into the tank, then it's sucked back from the tank into the radiator as the coolant cools and contracts. If much air is left in the radiator, expansion of the coolant doesn't force liquid out, and it doesn't generate enough vacuum on cooling to suck liquid in. Have to start with the radiator full or very nearly so for it to work as intended.

[Yaris Hilton]

If I do find my coolant's down like yours, I'm going to immediately top it up!

[CB900F2]

Hilton.. Did you have a chance to pop your coolant cap and take a look at the level? (cold)

thanks


If I do find my coolant's down like yours, I'm going to immediately top it up!

[TheSilkySmooth]

May need a new cap. Make sure the rubber gasket is clean. And only open that rad when cool. Try running heat on high and fan on hi to get the fluid circiulating through the heater core - that may move a bubble.

[CB900F2]

Are you able to pop open your rad cap when your motor is close and take a look at the coolant level and let us know what you find?

thanks TSS

May need a new cap. Make sure the rubber gasket is clean. And only open that rad when cool. Try running heat on high and fan on hi to get the fluid circiulating through the heater core - that may move a bubble.

[Yaris Hilton]

Hilton.. Did you have a chance to pop your coolant cap and take a look at the level? (cold)

thanks

Nope. Haven't. Guess I'd better.

[CB900F2]

Bump... Whats up guys, nobody wants to take a quick peak in your coolant filler neck??..

Are you scared of what you might find :evil: :eyebulge:

P.S.. Check it when the motor is fully cooled down.. :help:

[kurokoma-kun]

Bump... Whats up guys, nobody wants to take a quick peak in your coolant filler neck??..

Truly, why not? It's one of the easiest vital fluids to check... and its worth a look, I was very surprised to see how little coolant was in my reservoir tank before I topped up.

Now in my case I found I had somehow knocked the reservoir cap slightly open as I worked--just about a week later quite a bit of coolant had evaporated. The level being at or below the neck of radiator hose however, seems to be normal for me, its been that way every time I've checked. :iono:

[Yaris Hilton]

I did eventually look and found that all three of my family's Yarises have the system working properly, with the radiator neck full up to the cap, no air space, and the overflow bottle filled about halfway when cold.

[CB900F2]

Hilton/All...

Do you think there might be an air pocket or a defective rad cap??

Hilton.. If I understand your responce, does your overflow bottle rise to the full mark when the motor is warmed up and will then drop back down to the half way point of the overflow bottle when the motor cools?

I have ask the same question on another forum and few yaris (sedan) owners and they all have the same situation. Very odd...


I did eventually look and found that all three of my family's Yarises have the system working properly, with the radiator neck full up to the cap, no air space, and the overflow bottle filled about halfway when cold.

[ztlonewolf]

here's something you can try,when your car is cold,take off the cap,start the car and fill the radiater while the car is running,let it run until the thermostat opens up,the coolant level will drop,put in more coolant (just enough to fill it up to the top),once the coolant level starts to rise,put the cap back on the radiator and run it.that should take care of any air bubbles that may be in your system,once the car is cold again,check your levels and see if that helped.

[CB900F2]

Thanks wolf I will give it a try..

But the funny thing is my fluid level in my overflow bottle will rise about 1inch when the coolant becomes hot, and will also then lower when the engine cools off...so it seems fluid is flowing between the system and the overflow bottle..

thanks again!


here's something you can try,when your car is cold,take off the cap,start the car and fill the radiater while the car is running,let it run until the thermostat opens up,the coolant level will drop,put in more coolant (just enough to fill it up to the top),once the coolant level starts to rise,put the cap back on the radiator and run it.that should take care of any air bubbles that may be in your system,once the car is cold again,check your levels and see if that helped.

[Snappy]

When the engine is cold, try squeezing the upper radiator hose. I had a bad cap, and the same low fluid problem you have on one of my two 2007s. When you squeeze the hose, see if you hear/feel the air compressing in the filler neck, I got some give then a faint click. I replaced the cap (cheap for a Toyota part!) and no more problems. Also, I could squeeze the hose with the cap off, bringing the coolant level up to the top, then put the cap on, but when I checked again after driving and letting the car cool down, the low level returned.

[bboyl@rogers.com]

Same problem in my 2007 Yaris
Ill try a new cap too but it was disapearing slowly out of the resevoir over the last year now.
117000 Kms now so wont get warranty either if I know my dealer.
Dont see a leak at waterpump or any hoses either.

[N9QGS]

Hmm, my comments, I have checked my coolant while engine was cold from an overnight and I felt the coolant was lower than it should be like some of you have reported the the filler neck, and I have topped it off and come to find it was back down next time. one comment I am curious. Does anyone use a scan gauge II? I notice that my WT (coolant temperature fluctuates between 181 and 186, but if I stop at a traffic light and sit at idle in drive within id say a minute or minute and a half I am at 200ºF, it never goes any higher. and when I start driving it goes back down, mind you its been 30 degrees out. is this normal? I just don't remember seeing it crawl up during the summer like this. but I may not have paid as close attention.

[captainm27]

I have never touched my coolant. Usually when I take it to get an oil change, the receipt says they topped all the fluids. I just checked mine out today. My coolant is about an inch above the LOW line when cold. When the engine is hot, it's about 2 inches higher. I've own the car for a year and a half and never had any problems with the coolant. Is it normal for the Yaris engine to operate like this?

[Yaris Hilton]

Yep, that's OK.

[captainm27]

Ok good, then I feel much better.

[TheSilkySmooth]

My overflow bottle seems to be acting OK (at FULL hot and at LOW cold) so I dont want to take my cap off and introduce air into a properly functioning system. thats why I is chicken to take my cap off. FYU, I had a new dodge 318 pickup in 1996 and the rad hoses never got warm - even in the summer. That had me worried.

[ishara.liyanage]

Me too have the same problem in my yaris. But everything happened after a leak in radiator. It was a small leak, so it was repaired. After that this thing happened. It identical as Hilton's. No visible leaks at all. But still water level is below the filler neck.